<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>
  <input type="text"  v-model="num1">
  <input type="text"  v-model="num2">
  <input type="button" value="加" @click="f('+')">
  <input type="button" value="减" @click="f('-')">
  <input type="button" value="乘" @click="f('*')">
  <input type="button" value="除" @click="f('/')">
  <h1>结果:{{info}}</h1>
</div>
<script src="js/vue.min.js"></script>
<script>
  let v = new Vue({
    el:"body>div",
    data:{
      info:"",
      num1:"",
      num2:""
    },
    methods:{
      f(x){
        if(isNaN(v.num1)||isNaN(v.num2)){
          v.info="输入错误";
          return;
        }
        //eval() 方法可以直接将字符串以js代码的形式运行
        v.info = eval(v.num1+x+v.num2);
      }
    }
  })
</script>

</body>
</html>